Medical subject headings. Tree structures. 

 - Bethesda, Md. :    Medical Subject Headings Section, Library Operati ons, National Library of Medicine. 
 - v. ;    28 cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/> Subject headings -- Medicine -- Periodicals.<br/> Medicine -- Classification -- Periodicals.<br/> Medicine -- Periodicals. -- Periodicals.
<br/><br/><label>Dewey Class. No.: </label>REF 025.47 MED